1. Technical Area
The embodiments disclosed herein relate to a three dimensional automated warehouse that includes at least one pair of layered stacked racks that are oriented parallel to each other and a plurality of transferring shuttles implemented for every layer or every few layers of the stacked racks. The shuttles run in a horizontal direction and transfer packages in and out of the layered stacked racks. The disclosed embodiments also relate to a method of receiving and shipping to and from such a three dimensional automated warehouse.
2. Technical Background
A known example of a three dimensional warehouse is described in Patent Bulletin Heisei 5-21802. The three dimensional warehouse described in the Patent Disclosure is comprised of at least one pair of left and right layered stacks of racks, containing multiple layers. A transferring shuttle, which can run in a horizontal direction, is implemented for each layer of the stacked racks. The transferring shuttle is able to insert or extract the package into or from the left and right layered stacked racks.
The three dimensional automated warehouse described in the Patent Bulletin Heisei 5-21802 contains the receiving station at one end of the layered stacked rack, placed adjacent to the layered stacked rack, and the shipping station at the other end of the layered stacked rack, also placed adjacent to the layered stacked rack. These stations have multiple layers of stand-by conveyors, at the same level as the shelves of the layered stacked racks. Each conveyor can carry only one package at a time. The conveyors on the receiving station move the package towards the layered stacked rack, and the conveyors on the shipping station move the package away from the layered stacked racks. Each transferring shuttle can move up to the stations, and can exchange the package with the stand-by conveyor at the same level as the transferring shuttle.
An elevator device is implemented adjacent to the receiving and shipping stations, on the side away from the layered stacked racks. The elevator device is comprised of a central mast and elevator platforms placed at the left and right side of the central mast, which can move up and down. Each elevator platform also possesses a conveyor function. The elevator platform at the side of the receiving station can be positioned adjacent to receiving conveyors of an external transferring system; it can receive the package transferred from the receiving conveyor; it can move vertically; and it can then transfer the package to the appropriate stand-by conveyor of the receiving station to wait for further handling. Ultimately, the package is stored in the desired location in the layered stacked racks by the transferring shuttle. On the other hand, the elevator platform on the side of the shipping station can be positioned adjacent to a shipping conveyor of the external transfer system. The package, which is transferred to the stand-by conveyor from the layered stacked racks to the stand-by conveyor of the shipping station, can be delivered to the shipping conveyor.
In the three dimensional automated warehouse of the prior art described above, the route from the receiving conveyor of the external transfer system to the receiving station is one-way. The route from the shipping station to the shipping conveyor of the external transfer system is also one-way. This creates the problem of the receiving-shipping sequence becoming a single cycle. That is, in the receiving process, for example, after the package is transferred from the receiving conveyor to the stand-by conveyor of the receiving station via the elevator platform, the elevator platform must move back to the receiving conveyor while being empty. Likewise for the shipping process: the elevator platform must move to the stand-by conveyor of the shipping station, while being empty, to receive the next package. It is desirable to avoid such movement of the elevator platform while being empty.
Also, when the balance of the receiving and shipping quantities is disrupted for an external reason, one of the shipping or receiving devices may be at full capacity or suffer insufficient capacity (over-flow), while the other may be under-utilized. This, combined with the single cycle problem, has become a road block to capacity improvement.
Furthermore, with the construction of the prior art, if one of the devices is out of order, the response will be difficult and expensive. For example, if the elevator platform of the shipping side is out of order, the shipping would stop because the other elevator platform is exclusively for receiving. Even if the conveyor on the elevator platform on the receiving side and the stand-by conveyors are operated in both normal and reverse direction, the addition of a shipping conveyor to the external transfer system will be required, only to address this out-of-order situation.